1. Field of the Invention
Implementations of various technologies described herein generally relate to seismic data processing, and more particularly, processing seismic data using filters, such as 2D filters.
2. Description of the Related Art
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
Seismic exploration is widely used to locate and/or survey subterranean geological formations for hydrocarbon deposits. Since many commercially valuable hydrocarbon deposits are located beneath bodies of water, various types of marine seismic surveys have been developed. In a typical marine seismic survey, seismic streamers are towed behind a survey vessel. The seismic streamers may be several thousand meters long and contain a large number of sensors, such as hydrophones, geophones, and associated electronic equipment, which are distributed along the length of the each seismic streamer cable. The survey vessel also includes one or more seismic sources, such as air guns and the like.
As the seismic streamers are towed behind the survey vessel, acoustic signals, commonly referred to as “shots,” produced by the one or more seismic sources are directed down through the water into strata beneath the water bottom, where they are reflected from the various subterranean geological formations. Reflected signals are received by the sensors, digitized, and then transmitted to the survey vessel. The digitized signals are referred to as “traces” and are recorded and at least partially processed by a signal processing unit deployed on the survey vessel. The ultimate aim of this process is to build up a representation of the subterranean geological formations beneath the streamers. Analysis of the representation may indicate probable locations of hydrocarbon deposits in the subterranean geological formations.
The seismic streamers may be in an over/under configuration, i.e., one set of streamers being suspended above another set of streamers. Streamers in an over/under configuration may be towed much deeper than streamers in a conventional single configuration. As a result, broadband data (i.e., both high and low frequencies) may be acquired and the recorded data may be easily separated into up-going wavefields and down-going wavefields.
However, varying vertical separation between the upper streamers and the lower streamers and varying inline separation between the streamers during acquisition have caused problems in the processing of seismic data acquired using over/under configurations. In addition, application of 2D filters to process data acquired from such over/under configurations have also been problematic.